gistfile1.txt

arr = [1,2,3]

{{#each }}
  {{this}},
{{/each}}

produces:

1,2,3,

Can I do something to produce:

1,2,3

instead?

{{#each arr}}
{{item}}{{#unless last}},{{/unless}}
{{/each}}

helper.js

Handlebars.registerHelper("eachWithIndex", function(context, options) {
  var idx = 0, len = context.length, lastIdx = len - 1, last = false;
  var buf = "", currentContext;

  context.forEach(function(item) {
    last = idx === lastIdx;
    currentContext = { item: item, idx: idx, last: last }
    buf += options.fn(currentContext);
    idx++;
  });

  return buf;
});